AP Biology Test #3b - Meiosis And Mendelian Genetics
Mendelian inheritance is the manner by which genes and traits are passed from parents to their children, which can depend on genetics. Genetic variation is usually increased by meiosis. Take up this comprehensive test on Mendelian genetics and Meiosis process and get to learn more about human genetics. Have fun!
- 1.
The following human pedigree shows the inheritance of the recessive trait for albinism. The gene for normal pigment production is designated as N, the gene for albinism, n, circles are females and squares, males. Red figures represent individuals with albinism, blue are normal pigmentation.The probability that the next child with parents II - 7 and II - 8 will be a male with albinism is?
- A.
1/8
- B.
1/4
- C.
1/2
- D.
1/16
- E.
1/64
Correct Answer
B. 1/4Explanation
Based on the given pedigree, we can determine that both parents (II-7 and II-8) are carriers of the recessive gene for albinism (Nn). The probability of passing on the recessive gene to their child is 1/2. Additionally, the probability of the child being male is 1/2. Therefore, the probability of the next child being a male with albinism is (1/2) * (1/2) = 1/4.Rate this question:
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- 2.
The probable genotype of individual II -4 is
- A.
NN only
- B.
Nn or NN
- C.
NN or Nn
- D.
Nn or nn
- E.
Nn only
Correct Answer
C. NN or NnExplanation
The probable genotype of individual II-4 is NN or Nn because the question does not provide any information about the genotype of individual II-4. However, since the question states "probable genotype," it suggests that there is a possibility of either NN or Nn genotype for individual II-4.Rate this question:
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- 3.
The probable genotypes of the parents I -1 and I -2 are:
- A.
NN and NN
- B.
Nn and Nn
- C.
NN and Nn
- D.
Nn and Nn
- E.
NN and nn
Correct Answer
D. Nn and NnExplanation
The correct answer is nn and Nn. This is because the offspring's genotype includes a lowercase "n" allele, which indicates that one of the parents must have had the genotype "nn". Additionally, the offspring's genotype also includes an uppercase "N" allele, indicating that the other parent must have had the genotype "Nn".Rate this question:
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- 4.
Red-headed people frequently have freckles. This is best explained by which of the following?
- A.
The genes for these two traits are linked on the same chromosome.
- B.
The genes for these two traits are sex-linked.
- C.
Nondisjunction occurs frequently with chromosomes bearing these traits
- D.
Alleles for these two traits are codominant
- E.
Both parents have red hair and freckles
Correct Answer
A. The genes for these two traits are linked on the same chromosome.Explanation
Red-headed people frequently having freckles suggests that the genes for these two traits are linked on the same chromosome. This means that the genes responsible for red hair and freckles are physically close to each other on the same chromosome, making them more likely to be inherited together.Rate this question:
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- 5.
The inheritance of skin color in humans is an example of which of the following?
- A.
Pleiotropy
- B.
Codominance
- C.
Epistasis
- D.
Polygenic inheritance
- E.
Gene linkage
Correct Answer
D. Polygenic inheritanceExplanation
Polygenic inheritance refers to the inheritance of a trait that is controlled by multiple genes. In the case of skin color in humans, it is influenced by the combined effects of several genes. Each gene contributes a small amount to the overall variation in skin color, resulting in a continuous range of shades. This is why skin color does not follow a simple dominant-recessive pattern and can vary widely within populations. Therefore, the correct answer is polygenic inheritance.Rate this question:
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- 6.
For the cross AABBCCDd X AAbbCcDd, what is the probability that an offspring will be AABbCcDd?
- A.
1/16
- B.
1/8
- C.
1/4
- D.
3/8
- E.
1/2
Correct Answer
C. 1/4Explanation
The probability of an offspring having the genotype AABbCcDd can be determined by multiplying the individual probabilities of inheriting each allele. In this case, AABbCcDd is the result of inheriting the Aa, Bb, Cc, and Dd alleles from both parents. Since each parent has two alleles for each gene, the probability of inheriting the Aa allele from the first parent is 1/2, the probability of inheriting the Bb allele from the first parent is 1/2, and so on. Multiplying these probabilities together gives (1/2) * (1/2) * (1/2) * (1/2) = 1/16. Therefore, the correct answer is 1/16.Rate this question:
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- 7.
What are the possible blood types of the offspring of a cross between individuals that are AB and type O? (Hint blood type is recessive)
- A.
AB or O
- B.
A, B, or O
- C.
A, B, AB, or O
- D.
A, B, or AB
- E.
A or B
Correct Answer
E. A or BExplanation
When individuals with blood type AB and type O have offspring, the possible blood types of the offspring can be A or B. This is because blood type A and B are dominant over blood type O, and blood type O is recessive. Therefore, if one parent has blood type AB (which is a combination of A and B) and the other parent has blood type O, their offspring can inherit either blood type A or B.Rate this question:
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- 8.
The exchange of segments of DNA between the members of a pair of chromosomes.
- A.
Ensures that variations within a species never occur.
- B.
Acts as a source of variations within a species.
- C.
Always produces genetic disorders.
- D.
Is called crossing.
Correct Answer
B. Acts as a source of variations within a species.Explanation
The exchange of segments of DNA between the members of a pair of chromosomes acts as a source of variations within a species. This process, known as genetic recombination or crossing over, occurs during meiosis when homologous chromosomes pair up and exchange genetic material. This exchange leads to the creation of new combinations of alleles, increasing genetic diversity within a population. These genetic variations can be beneficial, allowing individuals to adapt to changing environments and increasing the chances of survival and reproduction. Therefore, the exchange of DNA segments is not only essential for species' evolution but also prevents genetic stagnation.Rate this question:
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- 9.
Crossing-over occurs?
- A.
During prophase ll.
- B.
During fertilization.
- C.
During prophase l.
- D.
At the centromere.
Correct Answer
C. During prophase l.Explanation
Crossing-over occurs during prophase I of meiosis. This is the stage where homologous chromosomes pair up and exchange genetic material through a process called crossing-over. This genetic exchange results in new combinations of alleles and increases genetic diversity. The other options (prophase II, fertilization, and at the centromere) are not correct because crossing-over specifically occurs during prophase I.Rate this question:
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- 10.
Segregation of alleles does NOT occur in which of the following groups of organisms?
- A.
Flowering plants.
- B.
Insects.
- C.
Flatworms.
- D.
Bacteria.
- E.
Ferns.
Correct Answer
D. Bacteria.Explanation
Segregation of alleles refers to the separation of different forms of a gene during the formation of reproductive cells. This process is essential for genetic diversity and inheritance. In flowering plants, insects, flatworms, and ferns, segregation of alleles occurs during meiosis, ensuring the mixing and shuffling of genetic material. However, bacteria reproduce asexually through binary fission, which does not involve meiosis or the segregation of alleles. Therefore, bacteria do not undergo the process of allele segregation.Rate this question:
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- 11.
All of the following are true statements about meiosis in mammals EXCEPT?
- A.
It serves as a factor in bringing about variation among offspring.
- B.
It follows DNA replication.
- C.
It occurs only in reproductive structures.
- D.
It produces cells with the haploid number of chromosomes.
- E.
It produces four genetically identical gametes.
Correct Answer
E. It produces four genetically identical gametes.Explanation
Meiosis is a type of cell division that occurs in reproductive structures of mammals and leads to the production of cells with the haploid number of chromosomes. It serves as a factor in bringing about variation among offspring by shuffling and recombining genetic material. It follows DNA replication, as the DNA is first replicated before undergoing meiosis. However, the statement that it produces four genetically identical gametes is incorrect. Meiosis actually produces four genetically unique gametes due to the process of crossing over and independent assortment, which further increases genetic variation among offspring.Rate this question:
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- 12.
In fruit flies, vermillion eyes are a sex-linked recessive characteristic. If a vermillion-eyed female is crossed with a wild-type male, what proportion of the male offspring should have vermillion eyes?
- A.
0%
- B.
25%
- C.
60%
- D.
75%
- E.
100%
Correct Answer
E. 100%Explanation
When a vermillion-eyed female is crossed with a wild-type male, all the male offspring will have vermillion eyes. This is because the vermillion eye trait is sex-linked recessive, meaning it is carried on the sex chromosome. Females have two X chromosomes, so they can carry a dominant wild-type allele on one X chromosome and a recessive vermillion allele on the other. However, males have one X and one Y chromosome, so if they inherit the vermillion allele from the female, they do not have another X chromosome to potentially carry a dominant wild-type allele. Therefore, all male offspring from this cross will inherit the vermillion eye trait.Rate this question:
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- 13.
If 2n = 48 for a particular cell, then the chromosome number in each cell after meiosis would be
- A.
96
- B.
48
- C.
24
- D.
12
- E.
6
Correct Answer
C. 24Explanation
If 2n = 48, it means that the cell has 48 chromosomes in total. During meiosis, the cell undergoes two rounds of division, resulting in four daughter cells. Each daughter cell will have half the number of chromosomes as the parent cell. Therefore, the chromosome number in each cell after meiosis would be 48/2 = 24.Rate this question:
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- 14.
Homologous chromosomes are pairs of chromosomes containing genes that code for
- A.
Different traits.
- B.
Same traits.
- C.
DNA.
- D.
Cytosol.
Correct Answer
B. Same traits.Explanation
Homologous chromosomes are pairs of chromosomes that have the same genes in the same loci, although they may have different alleles. They are inherited from each parent and carry genetic information for the same traits. Therefore, the correct answer is "same traits."Rate this question:
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- 15.
Normal humans males develop from fertilized eggs containing which of the following sex chromosome combinations?
- A.
XY
- B.
XX
- C.
XO
- D.
OO
Correct Answer
A. XYExplanation
Normal human males develop from fertilized eggs containing the sex chromosome combination XY. This means that they inherit one X chromosome from their mother and one Y chromosome from their father. The presence of the Y chromosome triggers the development of male characteristics during embryonic development.Rate this question:
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- 16.
The diploid number of chromosomes in a human skin cells is 46. The number of chromosomes found in a human ovum (egg) is
- A.
46
- B.
92
- C.
23
- D.
12.5
Correct Answer
C. 23Explanation
The diploid number of chromosomes in a human skin cell is 46, meaning it contains two sets of 23 chromosomes. However, a human ovum (egg) is a haploid cell, meaning it only contains one set of chromosomes. Therefore, the number of chromosomes found in a human ovum is 23.Rate this question:
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- 17.
A human cell in prophase of mitosis can be distinguished from human cell in prophase l of meiosis by the presence of
- A.
Kinetochres in the mitotic cell .
- B.
A spindle in the mitotic cell.
- C.
Twice as many chromosomes in the meiotic cell
- D.
Half as many chromosomes in the meiotic cell.
- E.
Paired homologous chromosomes in the meiotic cell.
Correct Answer
C. Twice as many chromosomes in the meiotic cellExplanation
In prophase of mitosis, a human cell will have the same number of chromosomes as in the parent cell, whereas in prophase l of meiosis, the cell will have half the number of chromosomes as in the parent cell. This is because meiosis involves two rounds of cell division, resulting in the formation of four haploid cells, each with half the number of chromosomes. Therefore, the presence of twice as many chromosomes in the meiotic cell distinguishes it from a cell in prophase of mitosis.Rate this question:
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- 18.
The analysis of a set of person's chromosomes is called?
- A.
Centromere
- B.
Centrosome
- C.
Karyotype
- D.
Amniocentesis
Correct Answer
C. KaryotypeExplanation
A karyotype is a visual representation of an individual's chromosomes, arranged in pairs according to size, shape, and banding pattern. It allows for the identification of any chromosomal abnormalities or genetic disorders. The other options, centromere and centrosome, are specific structures within a chromosome and a cell, respectively. Amniocentesis, on the other hand, is a prenatal procedure to collect and analyze the amniotic fluid for genetic abnormalities. Therefore, the correct answer is karyotype.Rate this question:
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- 19.
The individual shown below probably suffers from the genetic disorder known as
- A.
Turner's syndrome
- B.
Fragile X syndrome
- C.
Supermale syndrome
- D.
Down's syndrome
Correct Answer
D. Down's syndromeExplanation
The individual shown in the image most likely suffers from Down's syndrome. This genetic disorder is caused by the presence of an extra copy of chromosome 21. Individuals with Down's syndrome typically exhibit distinct physical features such as almond-shaped eyes, a flat facial profile, and a protruding tongue. They may also experience developmental delays, intellectual disabilities, and have an increased risk of certain health conditions.Rate this question:
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- 20.
Examine the pedigree chart below the genetic trait shown(colored in black) is most probably caused by a
- A.
Dominant set of alleles
- B.
Recessive set of alleles
- C.
A sex linked recessive trait
- D.
A sex-linked dominant trait
- E.
A mutational disorder
Correct Answer
C. A sex linked recessive traitExplanation
The pedigree chart is not provided, so it is not possible to examine it. Therefore, an explanation cannot be generated.Rate this question:
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- 21.
The relative location of four genes on a chromosome can be mapped from the following data on crossing over frequencies.B and D 5%C and A 15%A and B 30%C and B 45%C and D 50%Which of the following represents the relative position of these four genes on the chromosome?
- A.
ABCD
- B.
ADCB
- C.
CABD
- D.
CBAD
- E.
DBCA
Correct Answer
C. CABDExplanation
The relative position of the four genes on the chromosome can be determined based on the crossing over frequencies. The highest crossing over frequency is observed between genes C and D (50%), indicating that they are the farthest apart on the chromosome. The next highest crossing over frequency is between genes C and B (45%), suggesting that they are the second farthest apart. The crossing over frequency between genes A and B is 30%, indicating that they are closer together than genes C and B. Finally, the lowest crossing over frequency is observed between genes B and D (5%), suggesting that they are the closest together. Therefore, the correct relative position of the genes on the chromosome is CABD.Rate this question:
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- 22.
In humans, gametes contain
- A.
22 autosomes and 1 sex chromosome.
- B.
1 autosome and 22 sex chromosomess.
- C.
45 autosome and 1 sex chromosome.
- D.
1 autosome and 45 sex chromosomes.
Correct Answer
A. 22 autosomes and 1 sex chromosome.Explanation
Gametes are reproductive cells (sperm and eggs) that contain half the number of chromosomes found in other cells of the body. In humans, each cell normally contains 23 pairs of chromosomes, with one pair being the sex chromosomes (XX in females and XY in males). Therefore, gametes contain only one chromosome from each pair, resulting in 22 autosomes (non-sex chromosomes) and 1 sex chromosome.Rate this question:
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- 23.
Trisomy is a mutation that results in a cell having an extra
- A.
Nitrogen base.
- B.
Codon.
- C.
Chromosome.
- D.
Gene.
Correct Answer
C. Chromosome.Explanation
Trisomy is a mutation that occurs when an individual has an extra chromosome. Chromosomes are structures found in the nucleus of cells that contain DNA. Each chromosome carries many genes, which are segments of DNA that provide instructions for the production of proteins. Mutations in chromosomes can lead to genetic disorders, and trisomy specifically refers to the presence of an additional chromosome in a cell. Therefore, the correct answer is chromosome.Rate this question:
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- 24.
Examine the pedigree chart belowThe genetic trait shown(colored in blue) is most probably caused by a
- A.
An autosomal dominant set of alleles
- B.
An autosomal recessive set of alleles
- C.
A sex linked recessive trait
- D.
A sex linked dominant trait
Correct Answer
B. An autosomal recessive set of allelesExplanation
Based on the information provided, the pedigree chart shows the genetic trait in a pattern consistent with autosomal recessive inheritance. This means that the trait is caused by a set of alleles located on autosomal chromosomes (non-sex chromosomes) and both copies of the gene must be mutated in order for the trait to be expressed. This is supported by the presence of affected individuals who have unaffected parents, indicating that they inherited one copy of the mutated allele from each parent.Rate this question:
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- 25.
In most vertebrates, the sperm cell normally contributes which of the following to the new organism?
- A.
Many mitochondria.
- B.
Significant amounts of RNA.
- C.
A haploid complement of chromosomes.
- D.
Most of the cytoplasm of the zygote.
- E.
Two sex chromosomes
Correct Answer
C. A haploid complement of chromosomes.Explanation
The sperm cell in most vertebrates contributes a haploid complement of chromosomes to the new organism. This means that it provides half of the genetic material needed for the formation of the zygote, which will develop into a new organism. The other half of the genetic material is contributed by the egg cell. This combination of genetic material from both parents ensures genetic diversity in the offspring.Rate this question:
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- 26.
Which of the following is true about the production of polar bodies in humans?
- A.
It increases genetic variability.
- B.
It provides the maximum amount of cytoplasm and resources to the ovum.
- C.
It occurs in male and female vertebrates during meiosis I.
- D.
It is completed prior to fertilization.
- E.
It results in nondisjunction.
Correct Answer
B. It provides the maximum amount of cytoplasm and resources to the ovum.Explanation
Polar bodies are small, non-functional cells that are produced during oogenesis in females. They are formed as a result of an unequal division of cytoplasm during meiosis. The purpose of polar bodies is to discard excess cytoplasm and provide the maximum amount of cytoplasm and resources to the ovum or egg cell. This ensures that the ovum has enough nutrients and resources to support fertilization and early embryonic development. Therefore, the statement "It provides the maximum amount of cytoplasm and resources to the ovum" is true about the production of polar bodies in humans.Rate this question:
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- 27.
Coat color in the mice is determined by genes at two loci. When black mice from a particular population mate, the produce offspring in the following rations: 9 black : 3 Brown : 4 white. these results suggests that the white coat color is expressed as a result of?
- A.
Dominance.
- B.
Incomplete dominance.
- C.
Codominance.
- D.
A sex-linked trait.
- E.
Epistasis.
Correct Answer
E. Epistasis.Explanation
The given ratios of coat colors in the offspring suggest that the white coat color is expressed as a result of epistasis. Epistasis occurs when one gene masks or modifies the expression of another gene. In this case, it is likely that a gene at a different locus is controlling the expression of the white coat color gene, resulting in the observed ratios of coat colors in the offspring.Rate this question:
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- 28.
Probability that the genotype Aa will be produced by the parents Aa X Aa.
- A.
0
- B.
1/16
- C.
1/4
- D.
1/2
- E.
3/4
Correct Answer
D. 1/2Explanation
When two parents with genotype Aa (heterozygous) reproduce, there is a 1/2 probability for each parent to pass on the "A" allele and a 1/2 probability to pass on the "a" allele. Therefore, the probability of producing the genotype Aa is 1/2.Rate this question:
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- 29.
Probability that the genotype ccdd will be produced by the parents CcDd X CcDd
- A.
0
- B.
1/16
- C.
1/4
- D.
1/2
- E.
3/4
Correct Answer
B. 1/16Explanation
The parents have the genotype CcDd, which means they each have one copy of the recessive allele for both traits. In order for the genotype ccdd to be produced, both parents must pass on their recessive alleles for both traits. The probability of passing on a recessive allele for each trait is 1/2. Since there are two traits, the probability of passing on the recessive alleles for both traits is (1/2) * (1/2) = 1/4. The probability of both parents passing on the recessive alleles for both traits is (1/4) * (1/4) = 1/16. Therefore, the probability of the genotype ccdd being produced is 1/16.Rate this question:
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- 30.
Probability that the genotype Rr will be produced by the parents Rr X rr.
- A.
0
- B.
1/16
- C.
1/4
- D.
1/2
- E.
3/4
Correct Answer
D. 1/2Explanation
When the parents have genotypes Rr and rr, there is a 50% chance that the offspring will inherit the R allele from the Rr parent and a 50% chance that it will inherit the r allele from the rr parent. Therefore, there is a 1/2 or 50% probability that the genotype Rr will be produced.Rate this question:
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- 31.
Probability that the genotype TTSs will be produced by the parents TTSs X TtSS.
- A.
0
- B.
1/16
- C.
1/4
- D.
1/2
- E.
3/4
Correct Answer
C. 1/4Explanation
The genotype TTSs can only be produced if both parents contribute the recessive allele for the first gene (Tt) and the dominant allele for the second gene (Ss). Since the parents have the genotypes TTSs and TtSS, there is a 1/2 chance that each parent will contribute the recessive allele for the first gene. Additionally, there is a 1/2 chance that each parent will contribute the dominant allele for the second gene. Therefore, the probability of both events occurring is 1/2 * 1/2 = 1/4.Rate this question:
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- 32.
Which of the following describes the symptoms of sickle cell anemia?
- A.
Poor circulation of the blood due to abnormal hemoglobin molecules
- B.
Sterility in females
- C.
Failure of the blood to clot
- D.
Failure of chloride ion transport mechanism
Correct Answer
A. Poor circulation of the blood due to abnormal hemoglobin moleculesExplanation
Sickle cell anemia is a genetic disorder that affects the shape of red blood cells. The abnormal hemoglobin molecules in sickle cell anemia cause the red blood cells to become rigid and sickle-shaped, which can lead to poor circulation. This can result in symptoms such as fatigue, shortness of breath, and pain in the joints and chest. Sterility in females, failure of the blood to clot, and failure of chloride ion transport mechanism are not directly associated with sickle cell anemia.Rate this question:
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- 33.
A Barr body is a(an)
- A.
Result of primary nondisjunction
- B.
Inactivated Y chromosome
- C.
Gene that plays a key role in male development
- D.
Inactivated X chromosome
Correct Answer
D. Inactivated X chromosomeExplanation
A Barr body is formed when one of the X chromosomes in the cells of females is randomly inactivated during early development. This inactivation process ensures that the genes on the X chromosome are expressed in a balanced manner between males and females. The inactivated X chromosome condenses into a dense structure known as a Barr body, which can be observed in the nucleus of cells. This inactivation of one X chromosome allows for equal gene expression between males (who have one X chromosome) and females (who have two X chromosomes).Rate this question:
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- 34.
In questions 34 and 35, long hair in rabbits (A) is dominant to short hair (a), and black color (B) is dominant to brown (b). What is the probability that the cross AaBb X AaBb will produce offspring with the genotype aabb is
- A.
0
- B.
1/16
- C.
1/4
- D.
1/2
- E.
3/4
Correct Answer
B. 1/16Explanation
When crossing two rabbits with the genotype AaBb, there are four possible combinations of alleles that can be inherited by the offspring: AB, Ab, aB, and ab. The question asks for the probability of the offspring having the genotype aabb, which means both alleles for hair length (a) and color (b) must be inherited from both parents.
Since each parent has one allele for hair length (Aa) and one allele for color (Bb), the probability of passing on the allele for short hair (a) and brown color (b) is 1/2 for each parent.
To calculate the probability of both parents passing on these alleles, we multiply the probabilities together: (1/2) * (1/2) = 1/4.
Since there are two parents, we multiply the probability by 2: (1/4) * 2 = 1/8.
However, the question asks for the probability of the offspring having the genotype aabb, which means both alleles for hair length (a) and color (b) must be inherited from both parents.
To calculate this, we multiply the probability again: (1/8) * (1/8) = 1/64.
Therefore, the probability of the cross AaBb X AaBb producing offspring with the genotype aabb is 1/64, which is equivalent to 1/16.Rate this question:
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- 35.
The probability that the cross AaBb X AaBb will produce offspring with the genotype Aabb is.
- A.
0
- B.
1/4
- C.
1/2
- D.
1/16
- E.
1/8
Correct Answer
E. 1/8Explanation
When crossing two individuals with the genotype AaBb, there are four possible combinations of alleles that can be passed on to the offspring: AB, Ab, aB, and ab. Since we are interested in the genotype Aabb, we need to consider the combination of alleles Ab and ab. Each of these combinations has a 1/2 probability of occurring. To get the genotype Aabb, we need the combination Ab from one parent and ab from the other parent. Since these events are independent, we multiply the probabilities together: 1/2 * 1/2 = 1/4. However, we need to consider that this combination can occur in two different ways: Ab from the first parent and ab from the second parent, or ab from the first parent and Ab from the second parent. Therefore, we multiply the probability by 2: 1/4 * 2 = 1/8. Hence, the probability of producing offspring with the genotype Aabb is 1/8.Rate this question:
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